1. Field of the Invention
The present invention is broadly concerned with an improved process for the extraction of galactans from sources thereof using sonic energy. More particularly it is concerned with such a process which in preferred forms involves subjecting a mixture of Western larch chips and aqueous solvents to an acoustic field in order to enhance the recovery of arabinogalactan.
2. Description of the Prior Art
Arabinogalactan is a polysaccharide made up of galactose and arabinose units in the ratio of approximately five or six to one. Arabinogalactan is found in abundance, for example, in the wood of the Western larch tree (Larix occidentalis). While the arabinogalactan is present throughout the tree, the lower portion of the trunk, referred to as the "butt cut" contains so much arabinogalactan, of the order of 15% to 25% and more of the weight of the dry log, that the butt cut is neither good for lumber nor for pulping purposes. For years this portion of the tree has been discarded and left in the forest.
U.S. Pat. No. 2,073,616 describes a process for extracting arabinogalactan from larch wood wherein wood chips are subjected to leaching by an aqueous solvent which may contain dilute acid or alkali. This basic process has been followed in the industry for the last half-century without appreciable change, although there have been proposals for downstream purification of the arabinogalactan product.
The water extraction process for recovering arabinogalactan from larch is inherently expensive inasmuch as the process is generally capable of recovering only a relatively small fraction of the arabinogalactan present in the starting material. As a consequence, arabinogalactan has remained as expensive material, which has drastically limited its commercial usefulness.
It would therefore be a decided boon in the art to provide a method which would materially enhance arabinogalactan recovery without undue additional expense or difficulty; such a breakthrough would open up many new markets for the desirable arabinogalactan end product.